Apparatus for the binary digital coding of electric signals



March 8, 1960 ZEN m KIYASU E 2,923,053

APPARATUS FOR THE BINARY DIGITAL comm; OF ELECTRIC SIGNALS Filed July 7 1956 s Sheets-Sheet 1 1 ;;9.2A- JEy'ZC- l a l I l I l l l l United States Patent APPARATUS FOR THE BINARY DIGITAL CODING OF ELECTRIC SIGNALS Zen Iti Kiyasu, Nerima-ku, Tokyo-to, Hidero Uno, Na-

kano-ku, Tokyo-to, Shintaro Oshima, Musashino-shi, Tokyo-to, and Hajirne Enomoto, Ichikawa-shi, Chibaken, Japan, assignors to Kokusai Dcnshin Denwa Kabushiki, Kaisha, Tokyo-to, Japan Application July 17, 1956, Serial No. 598,424 Claims priority, application Japan July 19, 1955 7 Claims. (Cl. 332-11) This invention relates to an apparatus for coding electric input signals by means of binary digital system.

An essential object of this invention is to provide an improved apparatus for the binary digital coding in a pulse-code modulation system or in an electric digital computer.

According to this invention, binary digital coding of electric signals has been attained by using control signals the phases of which are modulated in accordance with the input signal waves by means of utilization of the physical property that phase of oscillation output wave of a parametrically excited resonator takes only either one of two different phases which differ 180 each other and the phase of said output wave is determined in accordance with the phase of control wave, oscillation principle of said resonator being described in the latter in connection with Figs. 1A and 13.

An apparatus which utilizes pulse-code modulation system has been proposed as a most ideal apparatus for the electric communication, but it is necessary to encode electric signals for the purpose of embodying said apparatus. In any electric computer also, it is necessary to encode various analogous data in order to introduce said data into the digital computer for carrying out electric counting.

It has been conventional to carry out coding of electric signals by converting amplitudes of the input signals to impulse signals by means of coding tube or level selector.

Differing from the above-mentioned apparatuses, this invention utilizes the physical property of the parametrically excited resonator and the principle of phase modulator to encode electric signals.

The novel features of this invention are set forth with particularity in the appended claims. This invention, however, both as to its construction and operation together with further objects and advantages thereof, may best be understood by reference to the following description, taken in connection with the accompanying drawings, in which:

Fig. 1A is a connection diagram of an example of parametrically excited resonator.

Fig. 1B is a connection diagram of another parametrically excited resonator.

Figs. 2A, 2B and 2C are wave forms and vector diagram for the description of the principle of the parametrically excited resonator.

Fig. 3 is a schematic connection diagram of an example of this invention.

Fig. 4 is a diagram indicating relations between phases of the output waves of four parametrically excited resonators and phase of output signalof the phase modulator in the example of Fig. 3.

Fig. 5 is a schematic connection diagram of another example of this invention.

Fig. 6 is a diagram indicating relations between phases of the output, waves of the parametrically excited resonators and phase of output signal of the phase modulator in the example of Fig. 5.

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Oscillation principle of the parametrically excited resonator is described herewith before description of this invention.

In Fig. 1A, in which one embodiment of a parametrically excited resonator to be used as an unit element of the apparatus of this invention is shown, each of two toroidal magnetic cores M and M is made of ferromagnetic material such as copper-zinc ferrite. On one ferro-magnetic core M are wound a primary coil L and a secondary coil L and on another ferro-magnetic core M are wound a primary coil L and a secondary coil L The coils L and L are connected in series to the output terminals 3 and 4 and the other coils L and L, are connected in series, with reverse polarities, to the input terminals 1 and 2 so that the input voltage supplied to the input terminals 1 and 2 may not induce any voltage to the output terminals 3 and 4. A condenser C is connected in parallel to, the secondary circuit composed of the secondary coils L and L to form a resonance circuit.

A damping resistance R is connected in parallel to the condenser C, but it may be, if necessary, omitted.

In Fig. 1B is shown another example of the parametrically excited resonator, in which the resonance circuit is formed by parallel connection of two ferro-electric condensers C and C which are connected in series, an inductance coil L and a damping resistance Ra, said circuit having input terminals 1 and 2 and output terminals 3 and 4.

When such an exciting current having a frequency 2)" as shown in Fig. 2A is supplied to the input terminals:

1 and 2 together with a superposed direct current and.

resonance frequency of the parametrically excited res-- onator is nearly equal to f, either one of two kinds of the output oscillation currents the frequencies of said currents being 1 and the phases of said currents being different by 180 each other, can be led out from the output terminals 3 and 4, said both kinds of the output oscillation currents being shown by such full line and broken line as shown in Fig. 2B.

The phase of said output current has a definite relation to the phase of the control current having a frequency f which is supplied to said resonance circuit at the initial period of the oscillation thereof. The phase relation between the exciting current having a frequency 2 and said output oscillation current having a frequency f becomes as shown in Figs. 2A and 2B, said phase relation being described more understandably in connection with the vector diagram in Fig. 2C. In Fig. 2C, taking the phase which lags by 45 from the standard phase X of the exciting current as 0, when the phase of the control current is within the range 0-180 or 180-360, the oscillation current takes, respectively, the vector (1) having an angle of or the vector (-1) having an angle of 270 due to pulling phenomenon.

Binary digital coding of electric signals in this invention is based on the above-mentioned physical property of the parametrically excited resonator and on the fact that if a frequency of any electric signal is doubled, the

phase angle of said signal is doubled also.

, oscillation frequency which is nearly equal to the resothe output side of the oscillator 0 to an exciting current having a frequency 21, a switching device E which sends 3 out the exciting current having a frequency 2 successively through the lines (I), (II) and (III), and a frequency tripler X for converting the current having a frequency f at the output side of the oscillator O to an output curfrom the output terminal 2a in the case that the original ang e 6 is within the range O-90 or 180-270 (90-180), and an output oscillation current the vector angle of which is -90 or 270 (direction (1) rent having a frequency 3 which is to be supplied to 5 in Fig. 2C) is led out from said terminal 2a in the case each of frequency converters B.M B.M B.M,,. that the original angle 6 is within the range 90-l80 or In apparatus in Fig. 3, when an electric continuous 270-360 (O-90). signal or samples of signals which are supplied to the in- Accordingly, it is possible to determine the second put terminal I are introduced in the phase modulator P.M. significant binary digit of the input signal by detecting to modulate the phase of output current of the oscillator 10 the phase of the output current Whioh is led out from the O in accordance with amplitude or amplitudes of said output terminal 2a. Furthermore, when an A.C. voltsignal or signals, a part of said modulated output current age having a frequency 21 and a phase angle 40 is having a frequency f is directly supplied to the parametriproduced at the output side of the frequency doubler M cally excited resonator Pa as a control signal to control by supplying a part of the output voltage of the frequency the phase of oscillation current of said resonator. Then, converter B.M to the frequency doubler M and the as described already in connection with Fig. 2C, an outthus obtained output voltage of said doubler M is sup put oscillation current the vector angle of which is 90 plied to the parametrically excited resonator Pa as the (direction 1) in Fig. 2C) is led out from the output control signal thereof after conversion of said output terminal la in the'case that the phase angle 0 of said voltage to a control voltage having a frequency and a control current is within the range O-18G, and an outphase angle 40, an output oscillation current the vector put oscillation current the vector angle of which is -90 angle of which is 90 having a vector .(direction (direction (l) in Fig. 2C) is led out from said terminal (1') in Fig. 2C) is led out from the output terminal 3a 1a in the case that said phase angle 0 is within the range in the casethat the original angle 0 is within the range 180-360. Accordingly, it is possible to determine the O-45, 90-135", 180-225 (-l35-180) or most significant binary digit of the input signal by detect- 270-3l5 (--4S-90), and an output oscillation ing the phase of the output current having a frequency f current of which vector is 90 or 270 (direction (1) which is led out from the terminal 1a, that is, by detecting in Fig. 2C) is led out from said terminal 3a. in the case the vector angle of said output current. that said angle 0 is within the other range than above- Next, when a part of the output current of the phase mentioned ranges. Accordingly, it is possible to deterrnodulator P.M., said output current having a frequency mine the third significant binary digit of the input signal fand a phase angle 0 is supplied to the frequency doubler by detecting he phase of the output current which is M the output voltage of said doubler becomes the one led out from the output terminal 3a. having a frequency 2 and a phase angle 29. Now, if the It is possible to carry out successive binary coding of just said output voltage is supplied to the frequency conthe input signals by repeating the same control as deverter Bit-i which is fed by a part of the output voltage scribed above in connection with the parametrically exof the tripler X frequency of the just said voltage being cited resonators P41 Pa whereby binary figures 3 output voltage of the frequency converter B.M becorresponding to the desirable digit places can be effectivecomes the one having a difference frequency f and a'phase ly obtained. angle 26. Theoretically, it is preferable to make an 40 The above-mentioned operating relations can be repreoutput voltage having a difference frequency f and a sented by the Table I. In Fig. 4 are shown said relations phase angle 20 by feeding the frequency converter B.M by phase diagram at the output side of the parametrically with a voltage having 'a frequency 1 instead of 3f, but in excited resonators. When electric processing is to be this case, there is an apprehension that the current havcarried out by using complement expression, the angle 0 ing a frequency f leaks. When said output voltage havwithin the range O-l80 can be conveniently used as ing a frequency f and a phase angle -26 is supplied to the complement. On the other hand, when only the the parametrically excited resonator Pa after phase phase of output current at the terminal 1a is so inverted inversion thereof to a voltage having a phase angle that vector angle of the oscillation output at said terminal (l8'=3 6) by a suitable means such as a transformer or becomes 90 or 270 in the case that the original 0 is by a suitable connection of the parametrically excited within the range 0-180 and becomes in the case resonator, an output oscillation current the vector angle that said angle 0 is within the range 0-l80, conof which is 90 (direction (1) in Fig. 2C) is led out ventional binary coding may be carried out.

Table I lginary binary binary 0 $5152 180--28 53 152 46 a t ili terminal terminal terminal 1a 2a 3a 1 (1s0-0) 90-135 l80-270 0-1s0 1 225-270 90-1s0 1 1s0-3e0 -1 (1a5-90) 1 (1s0-0) 315-3s0 270-360 1 l80-360 -.1 (45-0) (-s0-0) (1s0-0) The above description relates to only the case of conventional binary digital coding of electric signals.

However, it is easy to encode electric signals in reflected (Gray) binary codes. Such an example of this 6 a frequency doubler M to produce an output voltage having a frequency f and a phase 40 at the output side of said frequency converter B.M and the thus produced output voltage is supplied as the control voltage to the invention is schematically shown in Fig. 5, in which the 5 parametrically excited resonator Pa after conversion of same parts as the lfig. 3 are shown by same marks. In said phase angle 40 to (40-90) by means of a phase the apparatus 1n Fig. 5, when the input signal supplied shifter an output oscillation current having a vector to the input terminal I is first supplied to the phase moduangle of 90 or ---90 can be led out from the output lator P.M. so as totproduce a control signal current having terminal 4a. By detecting the phase angle of the output a frequency f and a phase angle 0 at the output side of current at the output terminal 4a can be determined the said modulator RM. and the thus produced signal current fourth significant binary digit. is dlrectly supplied to the parametrically excited resonator By repeating the same operations as those of the Pa;, an output oscillation current having a vector angle abovementioned operations can be carried out the sucof 90 or90 is obtained at the output terminal 1a cessive coding of the reflected (Gray) binary codes. according as the angle 0 is within the range 0-l80 or The above-mentioned relations are represented by the 180,-360 (0--l80). Accordingly, as in the case following Table II or by such phase diagrams at the of the apparatus in Fig. 3, it is possible to determine output side of the parametrically excited resonators as the most significant binary digit. When a part of output shown in Fig. 6.

Table II binary binary binary figure figure figure 0 at the B90- at the -2990 at the output output output terminal terminal terminal 1a 2a 3a 0-45 -90--45 1 -90-0 -1 45-90 1 -45-o 0-90 1 90-135 0-45 9o-1so 1a5-1s0 45-9o 1s0-270 27o-315 1s0-225 90-1s0 (-90--45 (-1s0-1a5) 1 a15-3s0 22s-270 180-270 (-45-0) (l35-90) (180-90) 1 voltage of the phase modulator P.M., frequency and phase angle of said voltage being, respectively, f and 0, is supplied to the parametrically excited resonator Pa after conversion of said phase angle 0 to (690) by means of a phase shifter an output oscillation current having a vector angle of 90 or --90 can be led out from the output terminal 2a according as the angle 0 is within the range 90-270 (90--90) or 270-90 (-90-90).

By detecting the output current at the output terminal 2a can be obtained the second significant binary digit. Furthermore, determination of the third significant binary digit can be similarly carried out by the following operation. That is to say, when a part of the output voltage of the phase modulator P.M., phase angle of said voltage being 0, is as same as the case in Fig. 3, supplied to the frequency converter B.M through a frequency doubler M to produce an output voltage having a frequency f and 'a phase angle at the output side of said frequency converter B.M and the thus produced output voltage is supplied as the control signal current to the parametrically excited resonator Pa after conversion of said phase angle 20 to (-20-90") by means of a phase shifter an output oscillation current having a vector angle of 90 or -90 can be led out from the output terminal 3a according as the original angle 0 is within the range 45-l35,.225-315 (--l--45) or with' in the other range. Determination of the fourth significant binary digit can be carried out by the following operation. That is to say, when a part of the output voltage of the frequency converter B.M frequency and phase angle of said voltage being, respectively, f and --20, is supplied to the frequency converter BM through While it has been described and shown particular embodiments of this invention, it will, of course, be understood that it would not be limited hereto, since many modifications may be made and this invention, therefore, contemplated by the appended claims to cover all such modifications as fall within the true spirit and scope of this invention.

What we claim is:

1. In an apparatus for the binary digital coding of electric signals, the combination of means for producing a first kind of control signal having a phase modulated according to input signal waves; means for producing a second kind of control signals, each of said signals hav ing a frequency which is equal to that of the control signal of the first kind and having a phase angle which is an integral multiple of the phase angle of the control signals of the first kind; parametrically excited resonators; means supplying said both kinds of the control signals to said resonators; and means for the detection of the oscillation output of each of the above-mentioned resonators, the binary digital coding of the input signals being carried out by said detection.

2. In an apparatus for the binary digital coding of electric signals, the combination of means for producing a first kind of control signal having a phase modulated according to input signal waves; means for producing a second kind of control signals, each of said signals having a frequency which is equal to that of the control signal of the first kind and having a phase angle which is an integral multiple of the phase angle of control signal of the first kind, said means consisting of frequency doublers and frequency converters; parametrically excited resonators; means for supplying said both kinds of the control signals to said resonators; and means for detesting the oscillation output of each of the above-mentioned resonators, the binary digital coding of the input signals being carried out by said detection.

3. In an apparatus for the binary digital coding of electric signals, the combination of means for producing a first kind of control signal having a phase modulated according to input signal waves; means for producing a second kind of control signals, each of said signals having a frequency which is equal to that of the control signal of the first kind and having a phase angle which is an integral multiple of the phase angle of the control signal of the first kind; parametrically excited resonators; means for supplying said both kinds of the control signals to said resonators; said means being connected so as to obtain reflected binary codes by converting the phase of a part of the control signal of the first kind and by converting the phases of the control signals of the second kind; and means for detecting the oscillation output of each of the above-mentioned resonators, the binary digital coding of the input signals beingcarried out by said detection.

4. In an apparatus for the binary digital coding of electric signals, the combination of means for producing a first kind of control signal having a phase modulated according to input signal Waves; means for producing a second kind of control signals, each of said signals having a frequency which is equal to that of the control signal of the first kind and having a phase angle which is an integral multiple of the phase angle of the control signal of the first kind; parametrically excited resonators, each of said resonators having a magnetic core made of term-magnetic material; means for supplying said both kinds of the control signals to said resonators; and means for detecting the oscillation output of each of the abovementioned resonators, the binary digital coding of the input signals being carried out by said detection.

5. In an apparatus for the binary digital coding of electric signals, the combination of means for producing a first kind of control signal having av phase modulated according to input signal waves; means for producing a second kind of control signals, each of said signals having a frequency which is equal to that of the control signal of the first kind and having a phase angle which is an integral multiple of the phase angle of the control signal of the first kind; parametrically excited resonators, each of said resonators containing ferro-electric condensers as the main elements thereof; means for supplying said both kinds of the control signals to said resonators; and means for detecting the oscillation output of each of the above-mentioned resonator, the binary digital coding of the input signals being carried out by said detection.

6. In an apparatus for the binary digital coding of electric signals, the combination of means for producing a first kind of control signal having a phase modulated according to input signal waves, said input'signal waves being a continuous signal wave; means for producing a second kind of control signals, each of said signals having a frequency which is equal to that of the control signal of the first kind and having a phase angle which is an integral multiple of the phase angle of the control signal of the first kind; parametrically excited resonators; means for supplying said both kinds of the control signals to said resonators; and means for detecting the oscillation output of each parametrically excited resonator, the binary digital coding of the input signals being carried out by said detection.

7. In an apparatus for the binary digital coding of electric signals, the combination of means for producing a first kind of control signal having a phase modulated according to input signal waves, said input signals being sampled signal waves; means for producing a second kind of control signals, each of said signals having a frequency which is equal to that of the control signal of the first kind and having a phase angle which is an integral multiple of the phase angle of the control signal of the first kind; parametrically excited resonators; means for supplying said both kinds of control signals to said resonators; and means for detecting the oscillation output of each of the above-mentioned resonator, the binary digital coding being carried out by said detection.

References Cited in the file of this patent UNITED STATES PATENTS 

